Mumtaz Yilmaz

Tepecik Training and Research Hospital, Ismir, İzmir, Turkey

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Publications (11)23.02 Total impact

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    ABSTRACT: OBJECTIVES: This case report presents our experience regarding a horseshoe kidney from live donor to be used as a renal transplant. MATERIALS AND METHODS: The recipient was a 48-year-old man with chronic renal failure owing to hypertension who had been on hemodialysis for 2 years. The donor was his 43-year-old sister who had an uncomplicated horseshoe kidney with negative results on a urinalysis. An aortogram showed that the arterial supply to the kidney consisted of 2 superior arteries (1 on each side) and 1 inferior accessory artery that was divided to feed the lower fused parenchyma of the kidney. RESULTS: Surgery was performed via a retroperitoneal lumbotomy incision; the left half of the kidney was mobilized. The left kidney was procured by clamping the inferior accessory renal artery, transecting the parenchyma within the demarcation boundary. The transplant kidney was placed in the recipient's contralateral iliac fossa. The graft vein was anastomosed to the recipient's external iliac vein, the artery to the external iliac artery, and the ureter to the bladder. After perfusing the graft, no urine leakage was detected from the transacted surfaces, and the graft began producing urine. There were no complications after surgery. The patient was discharged on the 10th day after surgery with a creatinine level of 0.07 μmol/L. Maintenance immunosuppressive treatment included tacrolimus, mycophenolate mofetil, and prednisolone. CONCLUSIONS: We believe using a horseshoe kidney as a renal allograft after a detailed preoperative evaluation may help expand the donor pool.
    Experimental and clinical transplantation : official journal of the Middle East Society for Organ Transplantation. 02/2013;
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    ABSTRACT: Background Online haemodiafiltration (OL-HDF) is considered to confer clinical benefits over haemodialysis (HD) in terms of solute removal in patients undergoing maintenance HD. The aim of this study was to compare postdilution OL-HDF and high-flux HD in terms of morbidity and mortality.Methods In this prospective, randomized, controlled trial, we enrolled 782 patients undergoing thrice-weekly HD and randomly assigned them in a 1:1 ratio to either postdilution OL-HDF or high-flux HD. The mean age of patients was 56.5 ± 13.9 years, time on HD 57.9 ± 44.6 months with a diabetes incidence of 34.7%. The follow-up period was 2 years, with the mean follow-up of 22.7 ± 10.9 months. The primary outcome was a composite of death from any cause and nonfatal cardiovascular events. The major secondary outcomes were cardiovascular and overall mortality, intradialytic complications, hospitalization rate, changes in several laboratory parameters and medications used.ResultsThe filtration volume in OL-HDF was 17.2 ± 1.3 L. Primary outcome was not different between the groups (event-free survival of 77.6% in OL-HDF versus 74.8% in the high-flux group, P = 0.28), as well as cardiovascular and overall survival, hospitalization rate and number of hypotensive episodes. In a post hoc analysis, the subgroup of OL-HDF patients treated with a median substitution volume >17.4 L per session (high-efficiency OL-HDF, n = 195) had better cardiovascular (P = 0.002) and overall survival (P = 0.03) compared with the high-flux HD group. In adjusted Cox-regression analysis, treatment with high-efficiency OL-HDF was associated with a 46% risk reduction for overall mortality {RR = 0.54 [95% confidence interval (95% CI) 0.31-0.93], P = 0.02} and a 71% risk reduction for cardiovascular mortality [RR = 0.29 (95% CI 0.12-0.65), P = 0.003] compared with high-flux HD.Conclusions The composite of all-cause mortality and nonfatal cardiovascular event rate was not different in the OL-HDF and in the high-flux HD groups. In a post hoc analysis, OL-HDF treatment with substitution volumes over 17.4 L was associated with better cardiovascular and overall survival.
    Nephrology Dialysis Transplantation 12/2012; · 3.37 Impact Factor
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    ABSTRACT: BACKGROUND: Recently, low serum estradiol levels have been associated with increased cardiovascular risk and mortality in non-uremic patient populations. We investigated the predictive value of serum estradiol levels for mortality in female hemodialysis patients. METHODS: One hundred and forty-seven prevalent female hemodialysis patients were included in March 2005 and followed up for 32 ± 16 months. Serum estradiol levels were determined by ELISA at baseline and studied in relation to cardiovascular and overall mortality. RESULTS: Mean serum estradiol level was 28.6 ± 15.4 pg/ml (5.7-81.3). Patients in the higher estradiol tertile were likely to be more often diabetic and to have more cardiovascular diseases and higher body mass index (BMI). Serum estradiol was inversely correlated with age and urea reduction rate and positively correlated with postdialysis body weight, BMI and hs-CRP levels. During the follow-up period, 52 (35.6 %) patients died. Patients who died were older, had shorter dialysis vintage, were more likely to have a history of diabetes and cardiovascular disease, and lower serum creatinine, albumin, hemoglobin, and higher hs-CRP levels than those who survived. In Cox regression analysis, estradiol levels, in a bimodal (U-shaped) distribution, along with diabetes, low serum albumin and high hs-CRP levels, were predictors for overall mortality. CONCLUSIONS: A U-shaped association between serum estradiol levels and cardiovascular and overall mortality was found in postmenopausal hemodialysis patients.
    International Urology and Nephrology 04/2012; · 1.33 Impact Factor
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    ABSTRACT: Low serum sodium levels have been associated with mortality both in patients with and without chronic kidney disease. In this study, we investigated this association in relation to glycemic control in hemodialysis (HD) patients. Between March and September 2005, 697 prevalent HD patients were enrolled in this prospective observational study and followed up for all-cause and cardiovascular mortality. The associations of serum sodium concentration with both overall and cardiovascular survival rates were studied. At baseline, mean predialysis serum sodium concentration was 138.4 ± 2.3 mEq/L (range: 130-145 mEq/L). Mild hyponatremia (< 135 mEq/L) was present in only 41 subjects (5.9%), and no patient had serum sodium level < 130 mEq/L. During 20.2 ± 6.2 months of follow-up, 119 patients (15.9%) died, 68 from CV causes. In adjusted Cox regression analysis, lowest sodium quartile was associated with 2.13-fold increased risk of overall mortality (95% confidence interval (CI) 1.14-3.98, P = 0.01, model chi-square 114.6, P < 0.001). As a continuous variable, each 1 mEq/L increase in predialysis sodium concentration was associated with a hazard ratio (HR) of 0.87 for overall mortality (95% CI 0.81-0.95, P = 0.002) and 0.86 for cardiovascular mortality (95% CI 0.78-0.96, P = 0.007). The predictivity of low serum sodium was prominent in diabetic subjects but not in nondiabetics. However, relationship between serum sodium and patient survival in diabetics was lost after adjustment for the HbA1c level: HR 0.91 (95% CI 0.78-1.05, P = 0.20). Low serum sodium concentration is associated with mortality only in those with diabetes. Furthermore, the impact of serum sodium on survival in these patients seems to be derived from poor glucose control.
    European Journal of Clinical Investigation 10/2011; 42(5):534-40. · 3.37 Impact Factor
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    ABSTRACT: Vascular calcification (VC), mainly due to elevated phosphate levels, is one major problem in patients suffering from chronic kidney disease. In clinical studies, an inverse relationship between serum magnesium and VC has been reported. However, there is only few information about the influence of magnesium on calcification on a cellular level available. Therefore, we investigated the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in bovine vascular smooth muscle cells (BVSMCs). BVSMCs were incubated with calcification media for 14 days while simultaneously increasing the magnesium concentration. Calcium deposition, transdifferentiation of cells and apoptosis were measured applying quantification of calcium, von Kossa and Alizarin red staining, real-time reverse transcription-polymerase chain reaction and annexin V staining, respectively. Calcium deposition in the cells dramatically increased with addition of BGP and could be mostly prevented by co-incubation with magnesium. Higher magnesium levels led to inhibition of BGP-induced alkaline phosphatase activity as well as to a decreased expression of genes associated with the process of transdifferentiation of BVSMCs into osteoblast-like cells. Furthermore, estimated calcium entry into the cells decreased with increasing magnesium concentrations in the media. In addition, higher magnesium concentrations prevented cell damage (apoptosis) induced by BGP as well as progression of already established calcification. Higher magnesium levels prevented BVSMC calcification, inhibited expression of osteogenic proteins, apoptosis and further progression of already established calcification. Thus, magnesium is influencing molecular processes associated with VC and may have the potential to play a role for VC also in clinical situations.
    Nephrology Dialysis Transplantation 07/2011; 27(2):514-21. · 3.37 Impact Factor
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    ABSTRACT: Chronic nephrotoxic effects of calcineurin inhibitors may be responsible for late allograft dysfunction and reduced allograft half-life. Mammalian target of rapamycin inhibitors (mTOR-i's), a newer class of immunosuppressant, do not have the chronic nephrotoxic effects shown with calcineurin inhibitors (CNI). Whether these drug classes have distinct features at the molecular level is not clear. Difference in gene expression profiles of kidney graft protocol biopsies from patients treated with CNI or mTOR-i's were investigated. Biopsies from patients using CNI (n=4) and mTOR-i-based treatments (n=4) were analyzed. The control group consisted of 5 biopsies obtained at the time of implantation (zero hour). Microarray hybridization was performed using the Affymetrix® GeneChip U133 plus 2.0 Array. In the CNI and mTOR-i groups, 64 up-regulated and 119 down-regulated genes were found compared to control subjects. A total of 29 genes in the CNI group and 101 genes in the mTOR-i group were up-regulated compared to each other. Despite similar clinical courses and histopathological appearances, different treatment strategies cause different gene expression profiles in kidney transplantation.
    Annals of transplantation: quarterly of the Polish Transplantation Society 06/2011; 16(2):76-87. · 0.82 Impact Factor
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    ABSTRACT: We investigated the frequencies and associated risk factors of cardiac arrhythmias and heart rate variability (HRV) in hemodialysis (HD) patients. One hundred fifty prevalent HD patients underwent 48-hour Holter monitoring. Holter monitoring was analyzed in 4 phases: early post-HD phase (12 hours), late post-HD phase (20 hours), pre-HD phase (12 hours), and HD phase (4 hours). Echocardiography was applied to measure the left ventricular mass index in a subgroup of patients (n: 52). Patients with ventricular premature contraction (VPC) were significantly older, had a longer HD duration, and higher hemoglobin (Hb) levels. Left ventricular mass index was significantly correlated with the frequency of VPC, during the HD and pre HD phases (r: 0.435, 0.312, respectively). In logistic regression analysis, patients with Hb level >11.9 g/dL (high tertile) had a 4.5-fold increased risk of VPC compared with those with Hb levels <10.8 g/dL (P: 0.04). In HRV analysis, age (P<0.001), and diabetes (P: 0.03) were found to be independent predictors of low standard deviation of all mean normal-to-normal RR intervals. Increased left ventricular mass index is associated with a high frequency of VPC in the pre-HD and HD periods. The occurrence of VPC is predicted by older age, longer dialysis duration, and higher Hb levels, while older age and diabetes are the determinants of HRV. The relation between higher Hb levels and the frequency of VPC might provide a clue for the explanation of the detrimental effect of higher Hb levels on HD patients.
    Hemodialysis International 04/2011; 15(2):250-5. · 1.44 Impact Factor
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    ABSTRACT: Strict volume control strategy provides better cardiac functions and control of hypertension in dialysis patients. We investigated the effect of this strategy on mortality and technique failure in peritoneal dialysis patients over a 10-year period. 243 patients were enrolled. Strict volume control by dietary salt restriction and ultrafiltration was applied. Mean systolic and diastolic blood pressures decreased from 138.4 ± 29.9 and 86.3 ± 16.8 to 114.9 ± 32.3 and 74.7 ± 18.3 mm Hg, respectively. Overall and cardiovascular mortality rates were 48.4 and 29.6 per 1,000 patient-years, respectively. In multivariate analysis, age, diabetes and baseline serum albumin level were independent predictors of overall mortality, and age, diabetes and baseline serum calcium of cardiovascular mortality. Residual diuresis and peritoneal equilibration test values were not related to mortality. Strict volume control leads to lower mortality than comparable series in the literature. Technique survival is better during the first 3 years, but not after 5 years.
    Blood Purification 02/2011; 32(1):30-7. · 2.06 Impact Factor
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    ABSTRACT: Longer dialysis sessions may improve outcome in haemodialysis (HD) patients. We compared the clinical and laboratory outcomes of 8- and 4-h thrice-weekly HD. Two-hundred and forty-seven HD patients who agreed to participate in a thrice-weekly 8-h in-centre nocturnal HD (NHD) treatment and 247 age-, sex-, diabetes status- and HD duration-matched control cases to 4-h conventional HD (CHD) were enrolled in this prospective controlled study. Echocardiography and psychometric measurements were performed at baseline and at the 12th month. The primary outcome was 1-year overall mortality. Overall mortality rates were 1.77 (NHD) and 6.23 (CHD) per 100 patient-years (P = 0.01) during a mean 11.3 ± 4.7 months of follow-up. NHD treatment was associated with a 72% risk reduction for overall mortality compared to the CHD treatment (hazard ratio = 0.28, 95% confidence interval 0.09-0.85, P = 0.02). Hospitalization rate was lower in the NHD arm. Post-HD body weight and serum albumin levels increased in the NHD group. Use of antihypertensive medications and erythropoietin declined in the NHD group. In the NHD group, left atrium and left ventricular end-diastolic diameters decreased and left ventricular mass index regressed. Both use of phosphate binders and serum phosphate level decreased in the NHD group. Cognitive functions improved in the NHD group, and quality of life scores deteriorated in the CHD group. Eight-hour thrice-weekly in-centre NHD provides morbidity and possibly mortality benefits compared to conventional 4-h HD.
    Nephrology Dialysis Transplantation 12/2010; 26(4):1287-96. · 3.37 Impact Factor
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    ABSTRACT: Nephrotoxic potential of mammalian target of rapamycin inhibitors (mTORi) is different from calcineurin inhibitors (CNI). The aim of this study is to investigate the interstitial fibrosis (ci) and tubular atrophy (ct) progression from the baseline to first year under a mTORi-based, CNI-free regimen. Thirty-five kidney transplant recipients who had to have adequate baseline and first year protocol biopsy were enrolled. Exclusion criteria were: the replacement of CNI at any time; acute deterioration in allograft functions; and serum creatinine level above 3 mg/dL at 12 months. Banff criteria were used for histopathological classification. Progression was defined as delta ci + ct ≥ 2 (difference between 12th month and baseline). Mean age of patients and donors were 34 ± 11 and 49 ± 10 years. Twelve patients had delayed graft function (DGF). The maintenance regimen consisted of sirolimus (n = 24) and everolimus (n = 11) with mycophenolate mofetil and steroids. Incidence of acute rejection was 25.7%. At baseline, the incidence of nil and mild fibrosis were 80% and 20%, respectively. At 12 months, 17.1% of patients had moderate, 40% had mild and 42.9% had nil fibrosis. Histological progression from baseline to first year was present in 34% of patients. In multivariate analysis the presence of DGF (P = 0.018) and deceased donor type (P = 0.011) were the most important predictors for fibrosis progression. Progression of graft fibrosis may be seen in one-third of patients under a mTORi-based regimen particularly manifested in deceased donor recipients with subsequent DGF.
    Nephrology 09/2010; 15(6):653-8. · 1.69 Impact Factor
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    ABSTRACT: One of the origins of cardiovascular disease in dialysis patients is arterial stiffness. The aim of our study was to assess the relationship between the calcium content of peritoneal dialysis (PD) solution and arterial stiffness. We enrolled into the study 49 PD patients who had been treated with the same PD solution for the preceding 6 months. The calcium content of the PD solution was 1.25 mmol/L in 34 patients (low-Ca group) and 1.75 mmol/L in 15 patients (high-Ca group). Study patients were followed for 6 months on the same PD prescription. Arterial stiffness was assessed by measurement of augmentation index (AI) and brachial pulse wave velocity (PWV) at baseline and at month 6 (SphygmoCor: Atcor Medical, West Ryde, NSW, Australia). Demographic data were recorded from patient charts. Mean age of the whole group was 51 +/- 11 years, prevalence of diabetes was 14%, duration of PD was 43 +/- 30 months, percentage of women was 45%, and percentage of patients using a cycler was 33%. We observed no differences between groups with regard to those variables or creatinine clearance, residual renal function, Ca, phosphorus, parathormone, C-reactive protein, lipid parameters, and use of phosphate binder with or without Ca content. Mean arterial pressure was higher in the high-Ca group, but the difference was not statistically significant (100 +/- 22 mmHg vs 88 +/- 18 mmHg, p = 0.06). At baseline, AI was significantly higher in the high-Ca group than in the low-Ca group (27% +/- 10% vs 21% +/- 9%, p < 0.05). Measurements of PWV were not different between the groups (8.4 +/- 1.1 m/s vs 8.5 +/- 1.7 m/s). Measurement of arterial stiffness parameters at month 6 revealed that PWV had increased in the high-Ca group (to 9.6 +/- 2.3 m/s from 8.4 +/- 1.1 m/s, p < 0.05), but had not changed in the low-Ca group (to 8.2 +/- 1.9 m/s from 8.5 +/- 1.7 m/s). The AI did not change in either group. These data suggest that Ca exposure through PD solution plays a role in the progression of arterial stiffness, which may be related to increased vascular calcification.
    Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis 02/2009; 29 Suppl 2:S15-7. · 2.21 Impact Factor